Two-cycle internal-combustion engine.



A. VON SCHMIDT.

TWO-CYCLE INTERNAL COMBUSTION ENGINE.

APPL|cAT|oN FILED SEPT. 7. |912.

1,1 69,891. Petented Feb. 1, 1916.

INVENTOR vention.

ARNOLD VoN SCHMIDT, 0F MUNICH, GERMANY, ASSILGNOR TO BUSCH-SUIlZER BROS.- DIESEL ENGINE COMPANY, 0F ST. LOUIS, MISSOURI, CORPORATION 0F MISSOURI.

TWO-CYCLE INTERNAL-COMBUSTION ENGINE.

weasel..

specitation of Letters Patent.

\ Application filed September 7, 1912. Serial No. 719,065.

To all whom t may concern.' y

Be it known that l, ARNOLD voN SCHMIDT. a subject of the Emperor of Germany, and resident of Munich, Germany, have invented a new and useful Improvement in Two- Cycle Internal-Combustion Engines', of which the following is a full, clear, and exact description, reference being fhad to the accompanying drawings, forming part of this specification. v

The new. arrangement of ports forming the object of my invention is illustrated in the accompanying drawings wherein- Figures 1 and 2 show the arrangement for a double acting and Figs. 4 and 5 the arrangement for a singleiacting engine, the latter embodying a modification ofrny in- Fig. 3 is a diagrammatic view illustrating a cross section through a cylinder in the ,zone ofthe inlet and exhaust ports. lig.- 1 is a longitudinal section through a cylinder on line m-m of Fig. 3. Fig. 2 is a longitudinal section on line jf/-y F ig. 3. Figs. 6 and 7 are detail views showing modifications hereinafter more fully described. l

My invention has relation to certain new and useful improvements in two-cycleinternalv combustion engines, and more particularly to means for providing an improved scavenging action.

Two-cycle internal combustion engines are known, in which the inlet ports for the air or charge are located in the same cylinder zone as the outlet ports. ln some of these engines, the charge enters the cylinder on one side of the same, is diverted toward the cylinder head by a deiecting surface on the piston, drives the exhaust gases in front of it, alongv the headv and the opposite cylinder -J wall, to the exhaust openings. lin another type of such two-cycle engines, a plurality of streams of the charge, radially introduced'` are directed toward the end of the cylinder by deflecting surfaces on the piston the direction of said streams being reversed by the cylinder head, so that they are combined, and flow back into the middle of ,the cylinder, driving the exhaust gases before them throughout their entire travel. lln

still other two-cycle engines, in which the charge is also introduced on one side of the Patented iran., i, raie.

cylinder, theyare not forced against the cylinder head by means of deflecting surfaces, but by the direction of some of the inlet slots, which are turned away from the outlet slots, so that the exhaust gases are also driven in front of the charge along the cylinder head and walls to the voutlet slots. lt is characteristic of all these methods of scavenging that the incoming charge drives the exhaust gas in front of it, and in its own direction of movement. This principle of scavenging is based upon the fact that the scavenging air must travel through a long' path back and forth in the cylinder and along the cylinder head and must therefore change its direction several times.

Scavenging by means of deflecting ribs or deiecting surfaces formed on the piston, is

particularly not suitable for Dieselmotors,

because in so doing, isolated air pockets a eA formed in which the fuel cannot enter i` its central injection, and also because in Diesel motors, the compression chamber is so small that the said pockets alone would be too large, and finally because the compression chamber of the Diesel motor lmust have a definite form, which cannot be obstructed by recesses, deflecting ribs or special, forms of the piston and head. According to the present invention, vthis old principle of scavenging is abandoned, and a new principle substituted, in which the exhaust gases are not driven in front of the fresh charge and-the consequent long travel and frequent change of direction, is done away with. llnstead of this, a new arrangement of the slots is employed. whereby the interior` of the cylinder is divided into several scavenging regions by a plurality of inlet slots inclined obliquely ings. As the free air jets spread out perpendicularly to their own direction, two adjacent scavenging streamsor jets act to compress the vquantity of burnt gas lying between them and thereby force it out throughthe proper outlet for' this particular region.

This fundamentally new arrangement is partcularly adapted for` those motors which scavenge only with fresh air, andis consenited' drives the piston downward and opens first the exhaust ports el. When the pressure of the combustion gases is diminished nearly to atmospheric pressure, thenA thel piston opens the inlet ports e.

Fig. 3 is a diagram of the new method of scavenging. TheM scavenging air vproduced in a known mannerby a.l scavenging pump enters through a number of scavenging openings, e e, directed 'obliquely toward the cylinder end (see Figs. 1 and 2). Each .two adjacent streams or collection of streams can spread out on all sides normally to theirdirection (see the small arrows in the elevation and plan), srince they How. freely through the-'cylinder space in consequence of their loblique direction. They consequently drive the exhaust gases, lying between them, out

through the exhaust openings d, d. which are suitablylocated lwithin this region. As the air currents expand freely onall sides and flow at an acute angle against each other they lose their velocity and spread out at the v cylinder end, whence the filling of the cylinder with fresh air proceeds equally to the outlet openings.

The number of the subdivisions of the cylinder space into scavenging regions, can be elther great or small, the mlmmum bemg i' two such regions (see, for example, Figs. 4

.- pleteness of the scavenging and consequently l oblique'ly lto the cylinder' axis, cut each other `at a -polnt'oj ,the cylinder axis-inside or outand 5). The number of the subdivisions depends upon the dimensionsof the cylinder, the number of revolutions andthe speed of the piston,that is to say, according to the necessary speed of the scavenging, since a small region is scavenged in much shorter time than a large region. Finally the subdivision 'depends'also upon the'req'uired comof the combustion. It will be seen from Fig.

f3, that vby the spreading of the scavenging l'between the same and thev cylinder wall are crowded out, andforced to escape from said region by thenearestexhaust opening,

t isentifrely immaterial whether the direccurrents on all sides, the' exhaust gases lying tions of.` the scavenging'stre'amsf, entering side the cylinder', in other' words,A form a cone, orv whether individualstreams meet each otherat-points, lying outside' the cylinder axis, or are inclined obliquely to each other (as in Figs. 4 and 5) It is also immaterial whether the outlet ports lie in approximately the same cylinder zone as the inlet ports, asin Figs. l and 2, or whether they are placed somewhat higher. The charge or scavenging streams may be introduced as a 'wh0le, as shown in the upper half of.' Fig. 3, Vor they may be broken up by bars or partitions, as shown in the -lower half of said figure, so that theyzdonot enter as solid streams, but as bundles ofstreams. In order not to aiect the direction of 'the incoming scavenging streams,'the edge of the piston ma be beveled or recessed, as shown at b1 in.v igs. 6 and 7. This, however, does not change the principle of eration.

Since the air currents, in consequence of their oblique direction relatively to the cylinder axis, penetrate into the midst vof the exhaust gases, and consequently present to them as large a surface of contact as possible, the exhaust gases-I in consequence of this intensive cooling effect of the scavenging air, contract suddenlyzto a fraction of the scavenging optheirv original volume, and are completely driven out of the cylinder by the scavenging air expandingjnormally to the direction of its iiow. The subsequent filling of the cylinder with a fresh charge is more compact than with the methods of scavenging above mentioned,v since the scavenging streams do not `iow along hot metal parts (such as defiectingA ribs or baliies and Cylinder walls)- from which they take up heat. Further more the new method of scavenging presents the advantage-that the scavenging streams, without first having their force diminished by deflecting ribs and long travel with several'changes of direction, are conducted in the shortest path and without encountering any obstructions, to the. cylinder head,.where -the fuel enters and where, consequently, a

complete cleaning out of the exhaust 'gases is most important. Thisnew scavenging principle is Yparticularly'advantageous for large cylinder dimensions, in which the old scavenging methods above mentioned diminish'the force of the scavenging streams, in iconsequence of the.' more than twice as long path of travel and of the numerous changes of direction. The -employment of this method of scavenging is also veryadvantageous in double acting internal combustion engines, particularly for double acting Diesel motors, the scavengin -of which by mea-ns of the methods referred to, acting on .-one side only was not possible, because the intervening piston rod caused-the scavenging air or charge to bestowed, diverted and set into whirls. It will be" seen from Figs. 2-and 3 thatthe piston rod does not ..standin the way of the complete loperation ofthis new4 method, butifon the contrary and lower guiding surfaces of the charge slots; or instead of one common charge port, two separated ports z' c'may be provided (see Fig. 2, right side);

Tn the embodiment of the invention shown in Figs. 4 and 5, the cylinder zone, containing the scavenging and exhaust slots, is

only divided into two scavenging regions,

and in such a way, that each two exhaust openings d and each two scavenging openings e lie opposite each other. The latter are, similarly to the scavenging slots shown in the lower half of Fig. 3, dividedinto avnumber of smaller slots ri There is consequently formed a bundle of streamsin each of the two scavenging regions. These bundles of the two opposite scavenging openings e, crowd the exhaust gases in the 'region lying between them to the two exhaust openings from both sides. By this construction, the two parts of the cylinder periphery, provided for the scavenging regions, are so large that they can beV subdivided into a large number of slots r,

' whereby another marked advantage is obtained. Thus some of the said slots, as thoseat one side, can be so placed that they are not only inclined toward the cylinder head, but so that they are also directed in pairs toward each other. ln this way, the two oppositely lying bundles f streams are given a tendency to form a wall, which divides the cylinder space intotwo parts. The scavenging action is thesame as in Figs 1-3, so that here' also the scavenging streams compress the exhaust gases between them. This particular manner of dividing and directing the air streams has Jfor result, that the charge is vmassed in the central region of the cylinderspace and particularly near the cylinder head, whereby a very tull charge of the cylinder is obtained. Tt is possible to direct the scavenging slots more or less directly toward each other than is represented in the drawing. The less thev are inclined toward each other, the less will be the massing of the charge.

l claim 1 A two-cycle internalv combustion en 1 having a cylinder whose side walls are provided with a plurality of inlet ports and lalso with a pluralityof exhaust ports arranged intermediately ot the inlet ports, the inlet ports having oblique walls to direct scavenging streams entering the cylinder through said ports inwardly and 'also toward an end of the cylinder so as' tn crowdj out the exhaust gases through the exhaust ports,su b

stantially as described.

2. A double-acting two-cycle internal combustion engine having a cylinder whose side -walls are provided with a plurality of inlet ports and also with aplurality of exhaust ports, arranged intermediately of the inlet ports, the inlet ports having oblique i walls to directv the entering scavenging streamsinwardly and also toward both ends of the cylinder so as to crowd out theexhaust gases through the exhaust stantially as described.

3. A two-cycle internal combustion engine, having a cylinder provided with-two inlet ports opposite to each' other, each of ports, suhsoy which is divided into a number of smaller ports which`are inclined both to the end the cylinder and to each other.

4. A doubleacting two cycle internal combustion engine having a cylinder whose side walls are provided with a plurality of. inlet ports and also with a plurality of ex- .haust ports, arranged intermediately of the'j inlet ports, the latter having separateI dis-v charge openings directed obliquely towardv the respective ends'of the cylinder'so'a's to crowd out the exhaust gases through the exhaustports, substantially as described..

5. A two-cycle internal combustion engine. having a cylinder-whose sidewalls areipro. vided with-a' plurality ,of inlet ports'xand also with a plurality` of exhaust poi-tsarranged intermediately of the inlet ports, the inlet ports having oblique walls to direct scavenging streams entering the cylinder therethrough inwardly and also toward the ends of the cylinder so as toy crowd out .the exhaust gases through the exhaust ports, and each inlet port being divided into a, plu'- rality of separate discharge passages to .break up the scavenging streams intriga-plurot rality ont ner streams, substantially Vas de-v scribed. i

6.- A two-cycle internal combustion. ene

with a plurality of exhiw orts varran'ged` intermediately of the inlet ports, the inlet` V ing inclined reversely to others of the group,

substantially as described.

` 7. A two-cyclg internal combustion engine aia having a cylinder whose side ywalls,are'pro-4k vided with a plurality oi inlet ports 'andalsd havinga'cyliiider whose side walls are provided with a, plurality of inlet 'portsand also with a pluralityof exhaust ports arranged intermediately of the inlet ports, the" inlet ports having oblique walls togdlrect scavenging streams entering .the cylinder through said ports inwardlyv and also toward an end of the cylinder sovas to crowd out the lexhaust gases through the exhaust ports, together with a- 'cylinder piston con-"` trolling said inlet and-exhaust piston having an unobstructed'en substantially as described.

8. A two-cycle internal combustion engine having a cylinder whose side walls are proorts, the surface,

vided with a plurality of inlet ports and also with a plurality ofexhaust ports arranged intermediately of th inlet ports, the

)piston having.: an unobstructed and peripherallybeveled end surface, substantially as described.

9. A two-cycle internal combustion engine havingl its-cylinder pro-vided with a series of alternately located inlet and exhaust `ports, the inlet ports having itnclined walls which cause the scavenging currents entering through theseA ports tol converge inwardly and also toward an end of the cylinder to thereby divide the body of gases to be scavenged and. crowd 'them toward the respective exhaust ports, substantially described. v

In testimony whereof, I have hereunto set my hand.

ARNOLD VON SCI-DHDT. Witnesses: l

RICHARD LEMP,

MATHILDE K. HEM 

